If you've been reading my blog for awhile, you'll know I'm not big on the whole "rules" aspect of writing. I firmly believe you should write what you want to write the way you want to write it, then worry about editing and marketing later.
However, I also know people who want to be writers have an insatiable longing for guides/rules/how-to's along the way. Since I happen to actually enjoy writing synopses, I decided to offer some suggestions that will, hopefully, make writing synopses less intimidating, more enjoyable and ultimately more successful.
1. For the first draft, just sit down and tell your story. Don't worry about making it perfect. Don't worry about language (I use slang all the time in first drafts). Don't worry about length. Just tell your story. I think this is the best way to convey a sense of your author's voice in a synopsis, and this is something you want to do. You don't want your synopsis to read like a dry laundry list of events.
2. When you edit, take out the obviously unnecessary first. Like adverbs. Make sure your verbs are doing a lot of work -- you don't have those adverbs anymore, after all.
3. Keep descriptions to a minimum. Unless a physical attribute of your characters is different enough to have an impact on your story (like, say, your hero has one eye), I wouldn't bother. Ditto the setting. I just say "castle," for instance, unless it's particularly large or small. If, however, the castle's on a cliff and somebody's going to fall off that cliff? I'd note that.
4. If you're writing a romance, the key thing to have in the synopsis is the development of the romance. Everything else is secondary -- your wonderful villain, your clever plot twists and, if you're writing historicals, the history. If you have to write a really bare-bones synopsis, this is especially important.
Be very clear about how the relationship develops. I've read far too many synopses where it just seems that suddenly, they're in love! Like Cupid's arrow got 'em. Unless you're writing a paranormal featuring Cupid? Not a good idea. I want to see the steps in that developing relationship, because that's going to determine whether or not I think the relationship will last.
5. Whatever you do, try not to water down/edit out your voice! This could be the only thing completely unique about your story. But that's not bad. Editors aren't thinking of one book; they're hoping to find somebody who'll write many books for the house, hopefully with growing sales, so it's your voice, not necessarily one particular book, that they're interested in.
So if you have some line or bit that you really like, keep it if you can, even if you might have to sacrifice elsewhere. In the synopsis I'm working on now, I mention a subplot romance thusly: "Cyne (the hero of the book) thinks they'll marry. Lizette (the heroine) thinks he's nuts."
Now, this doesn't sound particularly medieval-y, does it? But I like it because it implies conflict, the heroine's the cynic, not the hero (a bit different) and it also hints that this part might be a bit fun. I'm not particularly known, I don't think, for rollicking humor in my books (in real life? I wish I had a buck for everybody who suggested I become a stand-up comedienne). However, I do like to leaven the serious with some lighter moments, and if all goes as planned, this will be one of those lighter times. So I'm keeping it.
This also helps me avoid that "dry laundry list of events" feeling. It gives the synopsis some energy, in no small part because of the short nature of the sentences, in contrast to some longer ones that have gone before. I've had one word paragraphs in a synopsis when I wanted some dramatic impact.
6. Similarly, if I come up with a line of dialogue I think really works, in it goes. I know, I know -- most people say you shouldn't have dialogue in a synopsis. But I'm not talking a discussion. I'm saying, one, maybe two, lines, won't have an editor throwing up her hands in horror and declaring you Unfit To Be Published!
7. Have fun and let yourself get excited again by the idea that prompted you to consider writing that story in the first place.
Instead of thinking of writing a synopsis as some intimidating, horrible, yet necessary, chore, think of it as simply telling a story. Writers are storytellers, after all, so tell me your story -- which is surely a very exciting, fascinating story about a couple you really like, who met like this, who went on to have this really interesting, passionate relationship and you aren't gonna believe what happened ....
It's not so painful if you think of it like that. I hope.